fix(HEL-484): 中枢分时接口空 date 按当天查询

缺少或为空的 date 不再 400，按当天处理；显式历史日期保持原行为。

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

tests/test_chart_data_provider.py

@@ -193,8 +193,14 @@ class DatahubChartFallbackTests(unittest.TestCase):
 
     def test_datahub_timeout_or_empty_falls_back_to_eastmoney(self):
         fallback = LookbackChartClient()
-        for hub in (FakeHub(chart=None), FakeHub(error=RuntimeError("timeout"))):
+        for hub in (
+            FakeHub(chart=None),
+            FakeHub(error=RuntimeError("timeout")),
+            FakeHub(error=RuntimeError("datahub exploded")),
+            FakeHub(chart={"points": []}),
+        ):
             EastmoneyChartClient._cache.clear()
+            fallback.requests.clear()
             client = MarketChartClient(IfindHttpClient(), fallback, hub)
             payload = client.stock_intraday("000001")
             self.assertEqual(payload["trade_date"], "2026-09-07")

tests/test_datahub_bridge.py

@@ -64,9 +64,11 @@ class FakeClient(DatahubClient):
             meta={"tier": "official", "trade_date": "20240902", "stale": False, "staleness_seconds": 0},
         )
         self.paths: list[str] = []
+        self.calls: list[tuple[str, dict[str, Any]]] = []
 
     def get(self, path: str, params: dict[str, Any] | None = None) -> DatahubResponse:
         self.paths.append(path)
+        self.calls.append((path, {key: value for key, value in (params or {}).items()}))
         if TOKEN in json.dumps(params or {}) or TOKEN in path:
             raise AssertionError("token leaked into url")
         if self.error:
@@ -397,6 +399,20 @@ class DatahubBridgeTests(unittest.TestCase):
         self.assertEqual(len(chart["points"]), 1)
         self.assertEqual(chart["points"][0]["average"], 56.4)
         self.assertEqual(ok.client.paths, ["/v1/intraday/points"])
+        self.assertEqual(ok.client.calls, [("/v1/intraday/points", {"code": "601318"})])
+        self.assertNotIn("date", ok.client.calls[0][1])
+
+        timeout = DatahubBridge(
+            flags(intraday=(True, False)),
+            FakeClient(error=DatahubError("TIMEOUT", "datahub request timed out")),
+        )
+        self.assertIsNone(timeout.try_intraday("601318"))
+        broken = DatahubBridge(
+            flags(intraday=(True, False)),
+            FakeClient(error=DatahubError("INTERNAL", "datahub exploded")),
+        )
+        self.assertIsNone(broken.try_intraday("601318"))
+        self.assertFalse(DatahubSettings.load(environ={}, credentials={}).flags("intraday").read)
 
     def test_features_do_not_import_datahub_client(self) -> None:
         violations = []